Elastomer compositions for bonding to fluoropolymers

ABSTRACT

A method for increasing the adhesion of a first layer comprising a fluoropolymer substantially free of interpolymerized units derived from vinylidene fluoride to a second layer comprising a curable elastomer is described. The method comprises adding a dehydrofluorinating composition to the curable elastomer, contacting the layers and curing the layered article so formed. The resulting multilayer compositions and articles are also disclosed.

FIELD OF THE INVENTION

The invention relates to multi-layer compositions comprising afluoropolymer and a curable elastomer as well as to methods of producingsame. In another aspect, this invention relates to methods of improvingthe adhesion between a fluoropolymer and other dissimilar materials,such as, epichlorohydrin and nitrile-butadiene elastomers.

BACKGROUND OF THE INVENTION

Fluorine-containing polymers (i.e., fluoropolymers or fluorinatedpolymers), are an important class of polymers that include, for example,fluoroelastomers and fluoroplastics. Among this broad polymer class arepolymers of high thermal stability, polymers of extreme toughness, andpolymers exhibiting usefulness along a broad range of temperatures. Manyof these polymers also are almost totally insoluble in a wide variety oforganic solvents; see, for example, F. W. Billmeyer, Textbook of PolymerScience, 3rd ed., pp. 398-403, John Wiley & Sons, New York (1984).

Fluoroelastomers, particularly the copolymers of vinylidene fluoridewith other ethylenically unsaturated halogenated monomers such ashexafluoropropene, find particular utility in high temperatureapplications, such as in seal gaskets and linings. See, for example,Brullo, R. A., “Fluoroelastomer Rubber for Automotive Applications,”Automotive Elastomer & Design, June 1985, “Fluoroelastomers Seal UpAutomotive Future,” Materials Engineering, October 1988, and Grootaert,W. M., Millet, G. H., Worm, A. T., “Fluorocarbon Elastomers,”Kirk-Othmer, Encyclopedia of Chemical Technology, 4th ed., Vol. 8, pp.990-1005, John Wiley & Sons, New York (1993).

Fluoroplastics, particularly polychlorotrifluoroethylene,polytetrafluoroethylene, copolymers of tetrafluoroethylene andhexafluoropropylene, and poly(vinylidene fluoride), have numerouselectrical, mechanical, and chemical applications. Fluoroplastics areuseful, for example, as wire coatings, electrical components, seals, andin solid and lined pipes and piezoelectric detectors. See, for example,“Organic Fluorine Compounds,” Kirk-Othmer, Encyclopedia of ChemicalTechnology, Vol. 11, pp. 20, 21, 32, 33, 40, 41, 48, 50, 52, 62, 70, and71, John Wiley & Sons, New York (1980).

Multi-layer constructions containing a fluorinated polymer enjoy wideindustrial application; multi-layer fluoropolymer constructions findutility in, for example, fuel line hoses and related containers andhoses or gaskets in the chemical processing field. Increased concernswith evaporative fuel standards give rise to a need for fuel systemcomponents that have increased barrier properties to minimize thepermeation of fuel or fuel vapors through automotive components, such asfuel filler lines, fuel supply lines, fuel tanks, and other componentsof the engine's fuel or vapor recovery systems. Various types of tubinghave been proposed to address these concerns.

Adhesion between the layers of a multi-layered article may need to meetvarious performance standards depending on the use of the finishedarticle. A variety of methods can be used to increase the adhesionbetween a fluorinated polymer layer and a non-fluorinated polymer layer.An adhesive layer can, for example, be added between the two polymerlayers. U.S. Pat. No. 5,047,287 (Horiuchi et al.) discloses a diaphragm,suitable for use in automotive applications, that comprises a basefabric having bonded to at least one surface a fluororubber layer by anadhesive that includes an acrylonitrile-butadiene oracrylonitrile-isoprene rubber having an amino group. Blends of thefluoropolymer and the non-fluorinated polymer layer themselves are insome cases employed as an intermediate layer to help bond the two layerstogether. European Patent Application 0523644 (Kawashima et al.)discloses a plastic laminate having a polyamide resin surface layer anda fluororesin surface layer. The reference recognizes the difficultiesencountered when making laminates having a polyamide layer and afluororesin layer because of the incompatibility of the two materials.The laminate of the reference is prepared by use of an intermediatelayer composed of a blend of an aliphatic polyamide resin with afluorine-containing graft copolymer. U.S. Pat. No. 5,242,976 (Strasselet al.) discloses co-extruding vinylidene polyfluoride with an alkylpolymethacrylate and vinylidene polyfluoride composition.

Surface treatment of one or both of the layers sometimes is employed toaid bonding. Some, for example, have taught treating fluoropolymerlayers with charged gaseous atmosphere and applying subsequently a layerof a second material, for example a thermoplastic polyamide. E.g.,European Patent Applications 0185590 ((Jeno et al.) and 0551094 (Krauseet al.) and U.S. Pat. No. 4,933,060 (Prohaska et al.) and U.S. Pat. No.5,170,011 (Martucci).

Numerous methods of bonding have been proposed for multi-layerconstructions where the fluoropolymer layer contains a molecularstructure resulting from the inclusion of a vinylidene fluoride (VDF) orsimilar monomer unit. Similar monomers in this sense mean those monomersother than VDF which when polymerized, form monomer sequences similar topolymerized vinylidene fluoride. In general, these fluoropolymers willreadily dehydrofluorinate when exposed to a base. As a result, suchfluoropolymers undergo relatively facile adhesion promoting reactions.These other such monomers include ethylenically unsaturated monomerswhich, when incorporated into fluoropolymers, can produce a similar(including an identical) polymeric microstructure as the polymerizedVDF. These similarly formed polymers are also prone todehydrofluorination and subsequent adhesion promoting reactions. Ingeneral, the microstructure of a hydrogen bonded carbon atom betweenfluorine bonded carbon atoms creates a site reactive to a base. Thereactivity of a hydrogen bonded carbon is further enhanced when itscarbon atom is adjacent to, or attached to a carbon atom possessing acarbon bonded —CF3 group (supplied by HFP or 2-hydropentafluoropropylenefor instance) or another electron withdrawing group. Monomers suitablefor forming such hydrogen-bonded-carbon reactive sites include, but arenot limited to, VDF, 1-hydropentafluoropropene,2-hydropentafluoropropene, and trifluoroethylene.

The addition of a primary amine containing unsaturated compound to ahydrocarbon elastomer layer is disclosed as a method for increasing theadhesion to a layer comprising fluoropolymer comprising interpolymerizedunits derived from vinylidene fluoride in U.S. Pat. No. 5,512,225(Fukushi).

SUMMARY OF THE INVENTION

Multi-layer constructions containing a fluoropolymer without the VDFsegment or a similar easily dehydrofluorinated segment as discussedabove and below, are much more difficult to make with adequateinterlayer bond strength. These types of construction are desirablehowever, because fluoropolymers without a segment readily susceptible todehydrofluorinating are more chemically inert. For example, tubes orhoses or other containers used in fuel or chemical applications whereinertness, permeation reduction and interlayer adhesion improvement areimportant, will benefit from the improvement described in thisinvention.

As the above discussion illustrates, the combined features of curableelastomer compounds and fluoropolymer materials are a desirablecombination, particularly when the fluoropolymer possesses improvedchemical resistance or permeation properties.

In one aspect, this invention relates to a method of bonding afluoropolymer to a curable elastomer comprising the steps of: a)providing; (i) a fluoropolymer layer comprising a fluorine-containingpolymer derived from interpolymerized units of at least onefluorine-containing olefinically unsaturated monomer, with the provisothat if a perfluorinated monomer is present then at least one monomerthat contains hydrogen atoms is also present and with the furtherproviso that the monomer(s) include neither vinylidene fluoride nor amonomer which when polymerized forms a micro structure similar topolymerized vinylidene fluoride, (ii) a curable elastomer, and (ii) adehydrofluorinating composition, b) forming a layer comprising a mixtureof the curable elastomer and an effective amount of thedehydrofluorinating composition, c) forming a multi-layer article bycontacting the layer of the mixture with the layer comprising thefluoropolymer, and d) curing the multi-layer article under conditionssufficient to provide an interlayer adhesion between the curableelastomer layer and the fluoropolymer layer of at least 2 Newtons per cmof width. The dehydrofluorinating composition is preferably selectedfrom the group consisting of at least one of an organo-onium and anamidine. The curable elastomer is preferably selected from the groupconsisting of at least one of an epichlorohydrin-containing elastomer, anitrile rubber-containing elastomer, ethylene propylene dienecopolymers, silicone-containing elastomers, fluoroelastomers, andmixtures thereof.

In another aspect, the invention relates to a method of bonding afluoropolymer to a curable elastomer comprising the steps of a)providing; (i) a layer of a fluoropolymer comprising a copolymer derivedfrom interpolymerized units of a first monomer selected from the groupconsisting of hexafluoropropylene, a perfluoroalkyl vinyl ether, abranched perfluorinated monomer, and combinations thereof; a secondmonomer selected from the group consisting of tetrafluoroethylene,chlorotrifluoroethylene, a fully halogenated olefinically unsaturatedmonomer containing two carbon atoms and combinations thereof; a thirdmonomer selected from the group consisting of ethylene, propylene, anon-halogenated olefinically unsaturated monomer and combinationsthereof, (ii) a curable elastomer, and (iii) a dehydrofluorinatingcomposition, b) forming a layer comprising a mixture of the curableelastomer and an effective amount of the dehydrofluorinatingcomposition, c) forming a multi-layer article by contacting the layer ofthe mixture with the layer comprising the fluoropolymer, and d) curingthe multi-layer article under conditions sufficient to provide aninterlayer adhesion between the curable elastomer layer and thefluoropolymer layer of at least 2 Newtons per cm of width.

In still a further aspect, this invention relates to a method of bondinga fluoropolymer to a curable elastomer comprising the steps of: a)providing; (i) a layer of a fluoropolymer comprising a copolymer havinga hexafluoropropylene monomer content of at least 22% by weight and anethylene monomer content of at least 14% by weight wherein saidcopolymer is derived from interpolymerized units comprisinghexafluoropropylene, tetrafluoroethylene, and ethylene, (ii) a curableelastomer, and (iii) a dehydrofluorinating composition, b) forming alayer comprising a mixture of the curable elastomer and an effectiveamount of the dehydrofluorinating composition, c) forming a multi-layerarticle by contacting the layer of the mixture with the layer comprisingthe fluoropolymer, and d) curing the multi-layer article.

Another aspect of the invention relates to a layered article comprisinga first and second layer in intimate contact with one another. The firstlayer comprises a fluoropolymer substantially free of interpolymerizedunits derived from vinylidene fluoride or monomers which give a similarmicrostructure when polymerized. The second layer comprises a mixture ofa curable elastomer and a dehydrofluorinating composition. Theinterlayer adhesion between the first layer and the second layer is atleast 2 Newtons per cm of width. The a fluoropolymer used in the firstlayer may also be a fluorine-containing polymer derived frominterpolymerized units of at least one fluorine-containing olefinicallyunsaturated monomer, with the proviso that of a perfluorinated monomeris present then at least one monomer that contains hydrogen atoms isalso present and with the further proviso that the monomer(s) includeneither vinylidene fluoride nor a monomer which when polymerized forms amicro structure similar to polymerized vinylidene fluoride.

The invention also relates to a layered article comprising a first layercomprising a fluoropolymer derived from interpolymerized unitscomprising hexafluoropropylene, tetrafluoroethylene, and ethylene, and asecond layer comprising a mixture of a curable elastomer and adehydrofluorinating composition. The first and second layers are insubstantial contact with each other. The interlayer adhesion between thefirst and second layers is at least 2 Newtons per cm of width.

The layers discussed herein are intended to include the concept of asurface, such as that found when constructing a multilayered hose orother shaped article and not intended to be limited to flat shapes.Thus, a first layer or surface may be formed or shaped prior toapplication of the second material. The substantial contact of thesecond material to the first is to a surface of the first material.Either the fluoropolymer component or the curable elastomer componentmay be formed or shaped first. When a shaped article, such as a hose, isformed, either material may be on the inside or the outside of thearticle depending upon the intended use, such as where the temperatureresistance or chemical resistance is most needed.

An additional aspect of the invention also relates to a layered articlecomprising a first layer comprising a fluoropolymer derived frominterpolymerized units comprising hexafluoropropylene,tetrafluoroethylene, and ethylene and a second layer comprising amixture of a curable elastomer and a dehydrofluorinating composition.The fluoropolymer used in the first layer has a hexafluoropropylenemonomer content of at least 22% and an ethylene monomer content of atleast 14%. The two layers are in substantial contact with each other.

An additional aspect of the invention relates to a layered articlecomprising a first layer comprising a fluoropolymer having a melt pointof no more than 190° C. derived from interpolymerized units comprisinghexafluoropropylene, tetrafluoroethylene, and ethylene and a secondlayer comprising a mixture of a curable elastomer and adehydrofluorinating composition. The two layers are in substantialcontact with each other.

Examples of articles contemplated by this invention include a hose, acontainer, a gasket or a film.

DETAILED DESCRIPTION

Useful elastomers in the practice of this invention include those curedby a variety of curing agents. Such curing agents include peroxides,poly hydroxyl containing compounds (e.g. poly phenols), poly amines andsulfur or sulfur-containing curatives. These curing agents are suitablefor use with epichlorohydrin containing compounds, nitrile-butadienerubbers, ethylene propylene diene copolymers, silicone-containingelastomers and fluoroelastomers. The elastomers used may be a mixture ofone or more of these listed elastomers.

In the practice of this invention, the polyepichlorohydrin containingcompound (or gum (A)) is a solid, predominantly amorphous, highmolecular weight (i.e. greater than about 40,000 number averagemolecular weight) epichlorohydrin homopolymer gum, a copolymer gum ofepichlorohydrin with another cyclic ether (for example, ethylene oxide,propylene oxide, 2-butene oxide, ethyl glycidyl ether, and trimethyleneoxide), or a copolymers an terpolymer with another cyclic ether whichalso may allow for ethylenic unsaturation. Generally useful copolymergums will contain about 50 mol % of epichlorohydrin gum. Representativepolyepichlorohydrin containing compounds useful in this invention aredescribed in U.S. Pat. Nos. 3,158,580, 3,158,581, and 3,726,841.Commercially available polymer gums include Hydrin H homopolymers,Hydrin C copolymers, and Hydrin T terpolymers (ZEON, Louisville, Ky.).

The natural rubbers or synthetic rubbers derived from diene monomersuseful in this invention include synthetic elastomers, such asnitrile-butadiene rubbers and ethylene propylene diene terpolymers,which are sulfur or peroxide curable. Nitrile-butadiene rubbers includehigh molecular weight, amorphous, copolymers of 1,3-butadiene(CH₂═CH—CH═CH₂) and acrylonitrile (CH₂═CH—CN). Suitablebutadiene-acrylonitrile copolymers generally have acrylonitrile contentsof from 5 to 65% by weight, preferably from 10 to 45 by weight, andbutadiene contents of from 35 to 95% by weight, preferably from 55 to90% by weight.

Nitrile-butadiene rubbers also include hydrogenated nitrile-butadienerubbers in which some of the butadiene unsaturation is selectivelyhydrogenated. High temperature properties are generally superior becauseof this reduction in unsaturation. Commercially available hydrogenatednitrile-butadiene rubbers include Zetpol™ 2000 rubber available fromZeon Chemical, Inc.

Blends of nitrile-butadiene rubbers are also useful, such as the NBR/PVCblend commercially available from Miles, Inc., as Krynac™ NV850 blend.

Useful ethylene propylene diene terpolymers contain dienes such as1,4-hexadiene, dicyclo pentadiene, ethylidene norbornene. Commerciallyavailable ethylene propylene diene terpolymers include EPsyn™ 5206terpolymer, available from Copolymer & Rubber Chemical Corp.

Suitable fluorine-containing ethylenically unsaturated monomers for usein the preparation of the curable fluoroelastomer useful in thisinvention include the terminally unsaturated monoolefins typically usedfor the preparation of fluorine-containing elastomers. Such monomersinclude hexafluoropropene, chlorotrifluoroethylene,2-chloropentafluoropropene, perfluoroalkyl vinyl ethers, e.g.,CF₃OCF═CF₂ or CF₃CF₂OCF═CF₂, tetrafluoroethylene,dichlorodifluoroethylene, 1,1-dichlorofluoroethylene, vinylidenefluoride, vinyl fluoride, and mixtures thereof. Fluorine-free terminallyunsaturated monoolefin comonomers, e.g., ethylene or propylene may alsobe used as comonomers.

Useful dehydrofluorinating compositions useful in the inventionpreferably include one or more organo-onium compounds and arnidinecompounds. These are incorporated into the curable elastomer to improvethe bonding characteristics to the fluoropolymer. As used herein, theterm “dehydrofluorinating composition” refers to a composition which iscapable of improving the adhesion of the curable elastomer compounds tothe fluoropolymer layer. This is thought to be a result of creatingunsaturation in the fluoropolymer material.

As is known in the art, an organo-onium is the conjugate acid of a Lewisbase (e.g. phosphine, amine, ether, and sulfide) and can be formed byreacting said Lewis base with a suitable alkylating agent (e.g., analkyl halide or acyl halide) resulting in an expansion of the valence ofthe electron donating atom of the Lewis base and a positive charge onthe organo-onium compound. Many of the organo-onium compounds useful inthe present invention contain at least one heteroatom, i.e., anon-carbon atom such as N, P, S, O, bonded to organic or inorganicmoieties. One class of quaternary organo-onium compounds particularlyuseful in the present invention broadly comprises relatively positiveand relatively negative ions wherein a phosphorus, arsenic, antimony ornitrogen generally comprises the central atom of the positive ion, andthe negative ion may be an organic or inorganic anion (e.g., halide,sulfate, acetate, phosphate, phosphonate, hydroxide, alkoxide,phenoxide, bisphenoxide, etc.).

Many of the useful organo-onium compounds are described and known in theart. See, for example, U.S. Pat. No. 4,233,421 (Worm), U.S. Pat. No.4,912,171 (Grootaert et al.), U.S. Pat. No. 5,086,123 (Guenthner etal.), and U.S. Pat. No. 5,262,490 (Kolb et al.) all of whosedescriptions are herein incorporated by reference. Representativeexamples include the following individually listed compounds andmixtures thereof:

triphenylbenzyl phosphonium chloride,

tributylallyl phosphonium chloride,

tributylbenzyl ammonium chloride,

tetrabutyl ammonium bromide,

triphenyl sulfonium chloride,

tritolyl sulfonium chloride,

8-benzyl-1,8-diazabicyclo [5.4.0]-7-undecenium chloride,

benzyl tris(dimethylamino) phosphonium chloride and

benzyl(diethylamino)diphenylphosphonium chloride

A commercial source of a useful organo onium-containingdehydrofluorinating composition is Dynamar™ Rubber Chemical FX-5166available from Dyneon LLC of Oakdale, Minn. An effective amount of anorgano onium is that amount, usually stated in parts per hundred partsrubber (phr), necessary to give improved inter layer adhesion whencompared to a composition without any organo onium. Such improvedadhesion is preferably at least 2 Newtons per cm of width of the testsample. This will generally mean a level of onium between 0.25 to 7 phr,preferably between 0.5 to 5 phr.

Acid acceptors are also generally added prior to curing. Suitable acidacceptors include, for example, magnesium oxide, lead oxide, calciumoxide, calcium hydroxide, calcium carbonate and dibasic lead phosphite.Mixtures of more than one acid acceptor may be used in this invention.

Another example of a useful dehydrofluorinating compositions are theamidine base compounds, such as 1,8 diazabicyclo[4.3.0]undec-7-ene(DBU)and 1,5 diazabicyclo[4.3.0]non-5-ene(DBN) and salts thereof Examples ofDBU salts include salts of 1,8-diazabicyclo[5.4.0]undecene-7 withcarbonates, long chain fatty acids, carboxylates, aromatic sulfonates orcarboxylates, phenol salts, thiolic salts, etc. Typical examples areDBU-carbonate, DBU-stearate, DBU-naphthoate, DBU-P-hydroxy-benzoate,DBU-P-toluene-sulfonate, etc. Also included are unsubstituted orsubstituted phenol salts of 1,8-diazabicyclo-[5.4.0]undecene-7. Examplesof such compounds include the phenol salt of1,8-diazabicyclo-[5.4.0]undecene-7, the cresol salts of1,8-diazabicyclo-[5.4.0]undecene-7, resorcinol salts of1,8-diazabicyclo-[5.4.0]undecene-7 and hydroquinone salts of1,8-diazabicyclo-[5.4.0]undecene-7. A commercial source of usefulamidine-containing dehydrofluorinating compositions includes SANAPROVCAT SA102 DBU-octanoic acid salt and VCAT SA841 DBU/phenol novolacresin salts. (Sanapro Limited, Tokyo Japan). The amount of an amidinewhich is useful is that amount necessary to give improved interlayeradhesion. This will generally be between 0.25 to 7 phr. A preferredlevel is between 0.5 to 3.0 phr.

The solubility in the curable elastomer of the material selected as thedehydrofluorinating composition may affect the quantity required toreach a useful adhesion level. A higher solubility is thought to requirea lower additive level and thus may be preferred.

Additives useful in the curing of the elastomer, particularlyepichlorohydrin containing compounds, composition include imidazolines,diamines, internal salts of diamines, thioureas and polyphenol curingagents as discussed in U.S. Pat. No. 4,287,322 (Worm), incorporatedherein by reference. Additives useful in the curing of nitrile rubbercontaining compositions include peroxide compounds and sulfur-containingcompounds.

Methods of incorporation of the dehydrofluorinating composition and theother required additives into the curable elastomer compounds includeany of the usual rubber mixing devices, such as Banbury mixers, rollmills, or any other convenient mixing device. It has been found that atwo-roll rubber mill equipped with heat exchange means, e.g., coredchambers for cooling, is particularly suitable since the heat generatedby the high shearing forces in mixing can be dissipated and thetemperature more accurately regulated with this device than with devicesproviding other means for temperature control. The temperature duringmixing generally should not be allowed to rise above about 120° C. Themixture should be processed sufficiently to distribute the cross-linkingagents and other ingredients uniformly throughout the gum stock. About 5to 20 minutes or longer is recommended for this process.

Fluoropolymer materials may be described by broadly categorizing thefluoropolymers structurally into one of two basic classes. A first classincludes those fluorinated homopolymers or copolymers comprisinginterpolymerized units derived from vinylidene fluoride or monomerswhich give a similar polymer micro structure. The second class includesthose fluoropolymers which do not contain any significant level of suchmicro structure. For the purpose of this discussion, a copolymer isdefined as a polymeric material resulting from the simultaneouspolymerization of two or more dissimilar monomers and a homopolymer isderived from a single monomer. Thus, a fluoropolymer derived from threedifferent monomers, sometimes called a terpolymer, is herein classifiedas a copolymer.

The fluoropolymers useful in the practice of the invention are those ofthe second class. These fluoropolymers typically do not contain VDFmonomer (or any other similar monomer) at a level such that, whenpolymerized, produces a microstructure which is readily susceptible toreaction with a base, as described above. Hence, these fluoropolymersmay be referred to as “substantially non-vinylidene fluoride (non-VDF)containing fluoropolymers.” By “substantially non-VDF containing,” it ismeant that the fluoropolymer comprises less than 3%, preferably lessthan 1% by weight of interpolymerized units derived from VDF or othermonomers which produce a microstructure similar to VDF as describedabove. Most preferably, these fluoropolymers contain no VDF or similarmonomer units.

Useful fluoropolymers comprise copolymers derived from interpolymerizedunits of a first monomer selected from the group consisting ofhexafluoropropylene (HFP), perfluoroalkyl vinyl ethers (PFAVE), branchedperfluorinated olefinically unsaturated monomers and combinationsthereof; a second monomer selected from the group consisting oftetrafluoroethylene TFE, chlorotrifluoroethylene CTFE, fully halogenatedolefinically unsaturated monomers containing two carbon atoms andcombinations thereof; a third monomer selected from the group consistingof ethylene (E), propylene (P), non-halogenated olefinically unsaturatedmonomers and combinations thereof

Specific examples of useful fluoropolymer materials include copolymersof tetrafluoroethylene and at least 22% hexafluoropropylene (P) and 14%ethylene. A preferred fluoropolymer will have an ethylene content of atleast 14% and an HFP content of at least 24%. Useful fluoropolymers mayalso be characterized by melting point. Useful copolymers of TFE, E, andHFP will have a melting point of no greater than 190° C. and preferablyno greater than 170° C.

Fluoropolymers of this class can be prepared by methods known in thefluoropolymer art. Such methods include, for example, free-radicalpolymerization of hexafluoropropylene and tetrafluoroethylene monomerswith non-fluorinated ethylenically-unsaturated monomers. In general, thedesired olefinic monomers can be copolymerized in an aqueous colloidaldispersion in the presence of water-soluble initiators which producefree radicals such as ammonium or alkali metal persulfates or alkalimetal permanganates, and in the presence of emulsifiers such as theammonium or alkali metal salts of perfluorooctanoic acid. See forexample U.S. Pat. No. 4,335,238 or Canadian Pat. No. 2,147,045. They mayalso be prepared using a fluorinated sulfinate as a reducing agent and awater soluble oxidizing agent capable of converting the sulfinate to asulfonyl radical. Preferred oxidizing agents are sodium, potassium, andammonium persulfates, perphosphates, perborates, and percarbonates.Particularly preferred oxidizing agents are sodium, potassium, andammonium persulfates.

Aqueous emulsion and suspension polymerizations can be carried out inconventional steady-state conditions in which, for example, monomers,water, surfactants, buffers and catalysts are fed continuously to astirred reactor under optimum pressure and temperature conditions whilethe resulting emulsion or suspension is removed continuously. Analternative technique is batch or semibatch polymerization by feedingthe ingredients into a stirred reactor and allowing them to react at aset temperature for a specified length of time or by chargingingredients into the reactor and feeding the monomer into the reactor tomaintain a constant pressure until a desired amount of polymer isformed.

Useful multi-layer constructions may be made from the above materialsselected in such a manner that an interlayer adhesion value ofpreferably at least 2 Newtons per cm of width will be achieved.Appropriate selections of materials will result in interlayer adhesionof at least 5 Newtons per cm of width and most preferred selections willresult in interlayer adhesion of at least 10 Newtons per cm of width.

Methods known in the fluoropolymer art can be used to produce a bondedmulti-layer article wherein the fluoropolymer material is in substantialcontact with the curable elastomer compound. For instance, thefluoropolymer and the curable elastomer compound can be formed into thinfilm layers by known methods. The fluorinated layer and the curableelastomer layer can then be laminated together under heat and/orpressure to form a bonded, multi-layer article. Alternatively, thefluoropolymer and the curable elastomer compound, along with one or moreadditional layers where desired, can be co-extruded or cross-headextruded into a multi-layer article. See e. g., U.S. Pat. Nos.5,383,087, and 5,284,184, whose descriptions are incorporated herein byreference for such purpose. Useful articles include those where the twolayers are in substantial contact with each other.

The heat and pressure of the method by which the layers are broughttogether (e.g., coextrusion or lamination) should be sufficient toprovide adequate adhesion between the layers. It may, however, bedesirable to further treat the resulting multi-layer article, forexample with additional heat, pressure, or both, to provide furtheradhesive bond strength between the layers. One way of supplyingadditional heat when the multi-layer article is prepared by extrusionincludes delaying the cooling of the multi-layer article afterco-extrusion or lamination. Alternatively, additional heat energy may beadded to the multi-layer article by laminating or co-extruding thelayers at a temperature higher than necessary for rgmerely processingthe several components. Or, as another alternative, the finishedmulti-layer article may be held at an elevated temperature for anextended period of time. For example the finished multi-layer articlemay be placed in a separate means for elevating the temperature of thearticle, such as an oven or heated liquid bath. A combination of thesemethods may also be used.

A cure step may be desired or necessary to, for example, establish fullythe desired physical properties in the elastomer component of anyfinished article. Such cure step may include exposure to an elevatedtemperature, such as in a hot oven or in an autoclave treatment. Thisstep may be in addition to the thermal exposure of the other processsteps, e.g. lamination or coextrusion. Conditions and materials may beselected which accomplish both processes, e.g. the melt processing orlamination and curing, within the same temperature and pressure ranges.

Where the formation of a multi-layered article is a series of sequentialsteps, such as lamination of preformed sheets or multiple cross-headextrusions, an opportunity exists to treat the surface of one or bothmaterials prior to forming the layered article. A lamination ofpreformed sheets allows one or more surface treatments on either or bothmaterials before lamination. A cross-head extrusion process will allowone or more surface treatments on the first material formed, before theapplication of the second material.

Such surface treatments may consist of a solution treatment, such as asolvent. If the solvent contains a base, such as 1,8-diaza[5.4.0]bicycloundec-7-ene (DBU), treatment of the fluoropolymer will result in somedegree of dehydrofluorination. Such dehydrofluorination is thought to bebeneficial to promote adhesion to subsequently applied materials. Thisis particularly true when the subsequently applied material contains anyagent which is reactive to sites of unsaturation, such as those createdby dehydrofluorination.

Other methods of surface treatment include charged atmospheretreatments, such as corona discharge treatment or plasma treatment. Alsouseful are Electron beam treatment (E-beam). Such E-beam treatments mayalso be useful to promote the cure desired in the elastomer component.This step would preferably take place after the article is formed.

The methods of the present invention provide multi-layer articlesexhibiting ease of processability and improved inter-layer adhesive bondstrength between a fluoropolymer layer and a curable elastomer layer.Multi-layer articles of the present invention can have usefulness inarticles such as films, gaskets, containers, and tubing or hoses thatrequire specific combinations of barrier properties, high and lowtemperature resistance, and chemical resistance in articles withimproved interlayer adhesion. The methods and compositions of thisinvention are particularly useful for making multi-layer articlessuitable for use in motor vehicles, for example as fuel-line hoses, andfor films and blow-molded articles such as fuel tanks or bottles, wherechemical resistance and barrier properties are important.

The multi-layer articles of the present invention can have two, three,or even more separate layers. For example, the present inventioncontemplates a multi-layer article including a fluoropolymer layer, acurable elastomer layer, and optionally further comprising one or moreadditional layers comprising fluorinated or non-fluorinated polymers. Asa specific example, a bi-layer article can be prepared according to thepresent invention, the bi-layer article comprising a fluoropolymer layerand an epichlorohydrin (ECO) containing layer, wherein the describeddehydrofluorinating composition is mixed into the ECO containing layer.One or more additional layers comprising a fluorinated ornon-fluorinated polymer can, either thereafter or simultaneously bebonded to one or more of the fluoropolymer layer or the epichlorohydrincontaining layer, to produce a multi-layer article having three or morelayers.

EXAMPLE

In the following examples and comparative examples multi-layer articleswere prepared and the adhesion between the layers was evaluated. Alladditive concentrations are by weight based on weight of hydrocarbonelastomer (parts per hundred parts rubber (phr)) unless otherwiseindicated.

The fluoropolymers FP1 and FP2 were made in a manner similar to thefollowing description with adjustments in monomer levels as specified.

An internally enameled polymerization reactor having a total volume of195 l., provided with an impeller stirrer, is charged with 120 l. ofdeionized water, and 500 g. of ammonium perfluorooctanoate (in the formof 1667 g. of a 30% strength solution in water, commercial product ofthe 3M Company), 242 g. of diammonium oxalate monohydrate and 69 g. ofoxalic acid monohydrate are dissolved therein. After sealing thereactor, it is first flushed five times with nitrogen and subsequentlyonce with 1 bar of TFE.

After depressurization and heating to 43° C., 10 g. of n-pentane and 9kg. of HFP are pumped in via a line under moderate stirring. Thestirring is then increased to 210 rpm and 2.05 kg. of TFE and 133 g. ofET are fed into the reactor via the gas phase, so that a total pressureof 17 bar is achieved.

The polymerization is then initiated by pumping in a solution of 5 g. ofpotassium permanganate in 250 ml. of water and maintained bycontinuously feeding in 14 g. of potassium permanganate, dissolved in0.7 l. of water, per hour. The total monomer pressure of 17 bar isautomatically maintained by continuous feeding in of a mixture having amolar ratio of TFE:ET:HFP=2.3:1.7:1.

The reaction is stopped at a copolymer solids content, based on aqueousreaction medium used, of about 21% by venting of the monomer mixture.

The dispersion is then coagulated by means of the rapidly runningstirrer. The precipitated copolymer solid is separated off from theliquor, washed a number of times with water, dried in a nitrogenatmosphere for 15 hours at 110° C. and subsequently melt granulated.

Example 1

In Example 1, a 0.1 Kg sample of epichlorohydrin elastomer compound wasprepared using conventional methods with a two-roll mill by compoundingHydrin™ C2000L epichlorohydrin rubber (ECO), available from Zeon, Inc.,with 98 phr N-990 Carbon Black (Huber), 1.0 phr stearic acid (EMSciences), 1.0 phr nickel diisobutyldithiocarbamate (NBC), 1.0 phrnickel dimethyldithiocarbamate (NMC), both from Vanderbilt, 5 phr Dyphos(Associated Lead, Inc.), 0.5 phr Sulfasan (Monsanto) and 1.0 phrethylene thiourea (Aldrich Chemicals). To this compound was added 5.0phr calcium oxide powder (C. P. Hall) and 3.0 phr Dynamarim RubberChemical FX-5166, an organo-phosphonium compound commercially availablefrom Dyneon LLC.

A sheet about 2.5 mm thick was formed from the ECO compound by using atwo-roll mill. Composite samples were prepared with the ECO sheet and afluoropolymer consisting of a 375 micron thick film of a copolymer oftetrafluoroethylene (TFE), hexafluoropropylene (HFP) and ethylene (E),having a melt point of 168° C. This fluoropolymer (FP1) had monomerconcentration by weight of 24% HFP, 62% TFE and 14% ethylene.

The adhesion between the layers was tested using ASTM D-1876, commonlyknown as a “T-peel” test. To facilitate testing, a piece of 75 micronthick polyester (PET) film coated with a silicone release agent wasplaced between the ECO compound and the fluoropolymer layer along oneedge. The release-coated PET film was inserted about 1.25 cm along theshort edge of the 2.5 cm by 7.6 cm sample. The sheet of polyester didnot adhere to either of the layers and was used only to create afluoropolymer “tab” and a ECO “tab” to insert into the jaws of the testdevice.

The resulting 1 inch (2.54 cm) by 3 inch (7.62 cm) composites wereheated under pressure using a Wabash Hydraulic Press Co. heated platenpress at 320° F. (160° C.) and 100 psi (0.7 MPa) for 45 minutes. Thesamples were removed from the press and allow to cool to roomtemperature. Peel strength or adhesion was measured on the strips inaccordance with ASTM D 1976 (T-Peel Test). An Instron™ Model 1125tester, available from Instron Corp., set at a 4 inch/min (10.16 cm/Min)crosshead speed was used as the test device. The peel strength wascalculated as the average load during testing, and the value reportedwas the average of the samples. The average peel strength on the stripsfrom Example 1 is reported in Table 1.

Comparative Example C1

In Comparative Example C1, a sample was prepared and tested as inExample 1 except that no FX-5166 and calcium oxide was added to the ECOcompound. Test results are reported in Table 1.

Example 2

In Example 2, a 0.1 Kg sample of epichlorohydrin elastomer compound wasprepared using conventional methods with a two-roll mill by compoundingHydrin™ C2000L epichlorohydrin rubber (ECO), available from Zeon, Inc.,with 98 phr N-990 Carbon Black (tuber), 1.0 phr stearic acid (EMSciences, 1.0 phr NBC (Vanderbilt), 1.0 phr NMC (Vanderbilt), 5 phrDyphos (Associated Lead, Inc.) and 1.0 phr FC-5157, a 4-4′ sulfonylbisphenol compound available from Dyneon LLC. To this compound was added5.0 phr calcium oxide powder (C. P. Hall) and 3.0 phr FX-5166, availablefrom Dyneon LLC. Composite samples of this elastomer and FP 1 wereprepared and tested as in Example 1. Test results are reported in Table1.

Example 3

In Example 3, a 0.1 Kg sample of epichlorohydrin elastomer compound wasprepared using conventional methods with a two-roll mill by compoundingHydrin™ C2000L epichlorohydrin rubber (ECO), available from Zeon, Inc.,with 98 phr N-990 Carbon Black (Huber), 1.0 phr stearic acid (EMScience) 1.0 phr nickel diisobutyldithiocarbamate (NBC), 1.0 phr nickeldimethyldithiocarbamate (NMC), both available from Vanderbilt, 5 phrDyphos (Associated Lead Inc.), 0.5 phr Sulfasan (Monsanto), and 1.0 phrethylene thiourea (Aldrich Chemical). To this compound was added 5.0 phrcalcium hydroxide powder (C. P. Hall) and 2.0 phr tetrabutyl ammoniumchloride available from Aldrich Chemical. Composite samples of thiselastomer and FP 1 were prepared and tested as in Example 1. Testresults are reported in Table 1.

Example 4

In Example 4, a 0.1 Kg sample of epichlorohydrin elastomer compound wasprepared using conventional methods with a two-roll mill by compoundingHydrin™ C2000L epichlorohydrin rubber (ECO), available from Zeon, Inc.,with 98 phr N-990 Carbon Black (Huber), 2.5 phr stearic acid (EMScience) 1.0 phr nickel diisobutyldithiocarbamate (NBC), 1.0 phr nickeldimethyldithiocarbamate (NMC), both available from Vanderbilt, 5 phrDyphos (Associated Lead Inc.), 0.5 phr Sulfasan (Monsanto), and 1.0 phrethylene thiourea (Aldrich Chemical). To this compound was 1.5 phr of1,5 diazabicyclo[4.3.0]non-5-ene (DBN) available from Aldrich Chemical.Composite samples of this elastomer and FP 1 were prepared and tested asin Example 1. Test results are reported in Table 1.

Comparative Example C2

In Comparative Example C2, a 0.1 Kg sample of epichlorohydrin elastomercompound was prepared using conventional methods with a two-roll mill bycompounding Hydrin™ C2000L epichlorohydrin rubber (ECO), available fromZeon, Inc., with 98 phr N-990 Carbon Black (Huber), 2.5phr stearic acid(EM Science) 1.0 phr nickel diisobutyldithiocarbamate (NBC), 1.0 phrnickel dimethyldithiocarbamate (NMC), both available from Vanderbilt, 5phr Dyphos (Associated Lead Inc.), 0.5 phr Sulfasan (Monsanto), and 1.0phr ethylene thiourea (Aldrich Chemical). To this compound was added 1.5phr of 1,5 diazabicyclo[4.3.0]non-5-ene (DBN) available from AldrichChemical. Composite samples were prepared and tested as in Example 1except that the fluoropolymer was replaced with a copolymer made in amanner similar to FP 1 except the monomer ratios were HFP 20%, TFE 56%and ethylene 14%. The melt point of this polymer (FP2) was determined tobe 207° C. Test results are reported in Table 1.

TABLE 1 Summary of ECO Peel Test Results Peel Example ECO Fluoro-(Newtons/cm of # Composition polymer width) 1 ETU curative + FX-5166 +FP1 45.6 calcium oxide C1 ETU curative FP1 No Bonding 2 Bisphenolcurative + FX-5166 + FP1 36.9 calcium oxide 3 ETU curative + tetrabutylFP1 35.1 ammonium chloride + calcium hydroxide 4 ETU curative + DBN FP128.7 C2 ETU curative + DBN FP2 No Bonding

The data in Table 1 indicates the advantage of the compositions of theinvention as shown by the improved peel strength. The indication of “NoBonding” means the samples delaminated when they were inserted in thetest device.

Example 5

In Example 5, a 0.1 Kg sample of sulfur curable nitrite rubber compoundwas prepared using conventional methods with a two-roll mill bycompounding Nipol™ 1052 acrylonitrile butadiene rubber (NBR), availablefrom Zeon, Inc., with 44 phr N-990 Carbon Black (Huber), 1.0 phr nickeldiisobutyldithiocarbamate (NBC) (Vanderbilt), 2.0 phr2-mercaptobenzothiazole (T) (Monsanto), 1.0 phr tetramethylthiurammonosulfide (TMTM) (Monsanto) and 1.0 phr sulfur (Fisher). To thiscompound was added 2.2 phr 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and2.2 phr 2-Napthol, both Available from Aldrich Chemical.

A sheet about 2.5 mm thick was formed from the NBR compound by using atwo-roll mill. Composite samples were prepared with the NBR sheet and a375 micron thick film of a fluorinated copolymer FP 1.

The adhesion between the layers was tested using ASTM D-1876, commonlyknown as a “T-peel” test. To facilitate testing, a piece of 3 mil (75μm) polyester (PET) film coated with a silicone release agent was placedbetween the NBR compound and the fluoropolymer layer along one edge. Therelease-coated PET film was inserted about 1.25 cm along the short edgeof the 2.54 cm by 7.62 cm (1 inch by 3 inch) sample. The sheet ofpolyester did not adhere to either of the layers and was used only tocreate a fluoropolymer “tab” and a NBR “tab” to insert into the jaws ofthe test device.

The resulting 2.54 cm by 7.62 cm composites were heated under pressureusing a Wabash Hydraulic Press Co. heated platen press at 160° C. (320°F.) and 0.7 MPa (100 psi) for 45 minutes. The samples were removed fromthe press and allow to cool to room temperature. Peel strength oradhesion was measured on the strips in accordance with ASTM D 1976(T-Peel Test). An Instron™ Model 1125 tester, available from InstronCorp., set at a 10.16 cm/min (4 inch/min) crosshead speed was used asthe test device. The peel strength was calculated as the average loadduring testing, and the value reported was the average of the samples.The average peel strength on the strips from Example 5 is reported inTable 2.

Comparative Example C3

In Comparative Example C3, a composite sample of NBR and FP1 wasprepared and tested as in Example 5 except that no DBU or 2-Napthol wasadded to the nitrile rubber compound. Results for Comparative Example C3are reported in Table 2.

Example 6

In Example 6, a 0.1 Kg sample of peroxide curable nitrile rubbercompound was prepared using conventional methods with a two-roll mill bycompounding Nipol™ 1052 acrylonitrile butadiene rubber (NBR), availablefrom Zeon, Inc., with 44 phr N-990 Carbon Black (Huber), 3.0 phr MagliteD (C. P. Hall), 3.0 phr calcium oxide (C. P. Hall), 3.5 phr Luperco™11XL (Elf Atochem North America Inc.), 1.0 phr HVA-2 (Dupont) and 0.5phr triallyl isocyanurate (TAIC) (American Cyanamid Co.). To thiscompound was added 2.2 phr 1,5 diazabicyclo[4.3.0]non-10 5-ene (DBN) and2.2 phr 2-Napthol, both available from Aldrich Chemical.

Composite sample of this NBR and the fluoropolymer FP1 were prepared andtested as in Example 5. The test results for Example 6 are reported inTable 2.

Comparative Example C4

In Comparative Example C4, a sample was prepared and tested as inExample 6 except that no DBN or 2-Napthol was added to the nitrilerubber compound. Results for Comparative Example C4 are reported inTable 2.

Example 7

In Example 7, a 0.1 Kg sample of nitrile rubber compound was preparedusing conventional methods with a two-roll mill by compounding Nipol™1052 acrylonitrile butadiene rubber (NBR), available from Zeon, Inc.,with 44 phr N-990 Carbon Black (Huber), 1.0 phr nickeldilsobutyldithiocarbamate (NBC) (Vanderbilt), 2.0 phr2-mercaptobenzothiazole (MBT) (Monsanto), 1.0 phr tetramethylthiurammonosulfide (TMTM Monsanto) and 1.0 phr sulfur (Fisher). To thiscompound was added 2.2 phr 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)(Aldrich Chemical) and 2.2 phr Dynamar™ PPA-791 available from DyneonLLC.

Composite samples of this NBR and fluoropolymer FP1 were prepared andtested as in Example 5. The test results for Example 7 are reported inTable 2.

Example 8

In Example 8, a 0.1 Kg sample of peroxide curable nitrile rubbercompound was prepared using conventional methods with a two-roll mill bycompounding Nipol™ 1052 acrylonitrile butadiene rubber (NBR), availablefrom Zeon, Inc., with 44 phr N-990 Carbon Black (Huber), 3.0 phr MagliteD (C. P. Hall), 3.0 phr calcium oxide (C. P. Hall), 3.5 phr Luperco™101XL (Elf Atochem North America Inc.), 1.0 phr HVA-2 (Dupont) and 0.5phr triallyl isocyanurate (TAIC) (American Cyanamid Inc.). To thiscompound was added 2.0 phr DBU and 2.0 phr stearic acid, both availablefrom Aldrich Chemical.

Composite sample of this NBR and fluoropolymer FP1 were prepared andtested as in Example 5. The test results for Example 8 are reported inTable 2.

Example 9

In Example 9, a 0.1 Kg sample of peroxide curable nitrile rubbercompound was prepared using conventional methods with a two-roll mill bycompounding Nipol™ 1052 acrylonitrile butadiene rubber (NBR), availablefrom Zeon, Inc., with 44 phr N-990 Carbon Black, 3.0 phr Maglite D, 3.0phr calcium oxide, 3.5 phr Luberco™ 101XL, 1.0 phr HVA-2 and 0.5 phrtriallyl isocyanurate (TAIC). To this compound was added 2.0 phr DBU,2.0 phr stearic acid, and 2.0 phr FX-5 166, an organo phosphoniumcompound available from Dyneon LLC.

Composite sample of this NBR and fluoropolymer FP1 were prepared andtested as in Example 5. The test results for Example 9 are reported inTable 2.

Example 10

In Example 10, a 0.1 Kg sample of peroxide curable nitrile rubbercompound was prepared using conventional methods with a two-roll mill bycompounding Krynac™ acrylonitrile butadiene rubber (NBR), available fromBayer Corp. (Akron, Ohio), with 100 phr N-990 Carbon Black, 2.0 phrLuberco™ 101XL, and 0.5 phr triallyl isocyanurate (TAIC). To thiscompound was added 5.0 phr Dynamar™ FX-5166, 5.0 phr Hycar™ 1300×42amine terminated butadiene available from BF Goodrich, and 5.0 phrcalcium hydroxide (CP Hall).

Composite sample of this NBR and fluoropolymer FP1 were prepared andtested as in Example 5. The test results for Example 10 are reported inTable 2.

Example 11

In Example 11, a 0.1 Kg sample of peroxide curable nitrile rubbercompound was prepared using conventional methods with a two-roll mill bycompounding Nipol™ 1052 acrylonitrile butadiene rubber (NBR), availablefrom Zeon, Inc., with 44 phr N-990 Carbon Black, 3.0 phr Maglite D, 3.0phr calcium oxide, 3.5 phr Luberco™ 101XL, 1.0 phr HVA-2 and 0.5 phrtriallyl isocyanurate (TAIC). To this compound was added 3.3 phr ofZEONET PB™, said to be a benzotriazolate phosphonium (Zeon Chemical,Louisville, Ky.) and 8.3 phr calcium hydroxide (C. P. Hall).

Composite sample of this NBR and fluoropolymer FP1 were prepared andtested as in Example 5. The test results for Example 11 are reported inTable 2.

Comparative Example C5

In Example C5, a 0.1 Kg sample of peroxide curable nitrile rubbercompound was prepared using conventional methods with a two-roll mill bycompounding Nipol™ 1052 acrylonitrile butadiene rubber (NBR), availablefrom Zeon, Inc., with 44 phr N-990 Carbon Black, 3.0 phr Maglite D, 3.0phr calcium oxide, 3.5 phr Luberco™ 101XL, 1.0 phr HVA-2 and 0.5 phrtriallyl isocyanurate (TAIC). To this compound was added 3.3 phr ofZEONET PBT, said to be a benzotriazolate phosphonium (Zeon Chemical,Louisville, Ky.) and 8.3 phr calcium hydroxide (C. P. Hall).

Composite samples were prepared and tested as in Example 5, except thatthe fluoropolymer FP1 was replaced with fluoropolymer FP2. Test resultsare reported in Table 2.

Example 12

In Example 12, a 0.1 Kg sample of peroxide curable nitrile rubbercompound was prepared using conventional methods with a two-roll mill bycompounding Krynac™ acrylonitrile butadiene rubber (NBR), available fromBayer Corp. (Akron, Ohio), with 100 phr N-990 Carbon Black, 2.0 phrLuberco™ 101XL, and 0.5 phr triallyl isocyanurate (TAIC). To thiscompound was added 2.5 phr tetrabutyl ammonium chloride, available fromAldrich Chemical (Milwaukee, Wis.), 5.0 phr Hycar™ 1300×42 amineterminated butadiene available from BF Goodrich, and 5.0 phr calciumhydroxide (CP Hall).

Composite sample of this NBR and fluoropolymer FP1 were prepared andtested as in Example 1. The test results for Example 12 are reported inTable 2.

TABLE 2 Summary of NBR Peel Test Results Peel Example NBR Fluoro-(Newtons/cm of # Composition polymer width)  5 S curative + DBU +2-Napthol FP1 16.9 C3 S curative FP1 No Bonding  6 Peroxide curative +DBN + 2- FP1 35.1 Napthol C4 Peroxide curative FP1 No bonding  7Peroxide curative + DBU FP1 16.9  8 Peroxide curative + DBU + FP1 10.4Stearic Acid  9 Peroxide curative + DBU + FP1 14.0 Stearic Acid + FX5166 10 Peroxide curative + Hycar FP1 10.4 1300x42 + FX 5166 11 Peroxidecurative + ZEONET FP1 42.9 PB ™ C5 Peroxide curative + ZEONET FP2 NoBonding PB ™ 12 Peroxide curative + Hycar ™ FP1 3.73 1300x42 +tetrabutyl ammonium chloride

The data in Table 2 indicates the advantage of the compositions of theinvention as shown by the improved peel strength. The indication of “NoBonding” means the samples delaminated when they were inserted in thetest device.

What is claimed is:
 1. A layered article comprising a first and secondlayer in intimate contact with one another wherein: a) the first layercomprises a fluoropolymer having less than 3% by weight ofinterpolymerized units derived from vinylidene fluoride or a monomerthat gives a similar microstructure to polymerized vinylidene fluoridewhen polymerized, and b) the second layer comprises a mixture of acurable elastomer and a dehydrofluorinating composition selected fromthe group consisting of an organo-onium compound, an amidine compound,or a mixture of one or more of an organo-onium compound and an amidinecompound.
 2. A layered article according to claim 1 wherein the curableelastomer is selected from the group consisting of epichlorohydrincompounds, nitrile-butadiene rubbers, ethylene propylene dienecopolymers, and silicone-containing elastomers, and mixtures thereof. 3.A layered article according to claim 2 wherein the curable elastomer isan epichlorohydrin compound.
 4. A layered article according to claim 1wherein the dehydrofluorinating composition is an organo-onium compoundor a mixture of organo-onium compounds.
 5. A layered article accordingto claim 4 wherein the organo onium comprises a phosphonium.
 6. Alayered article according to claim 1 wherein the dehydrofluorinatingcomposition is an amidine compound or a mixture of amidine compounds. 7.A layered article according to claim 6 wherein the amidine comprises1,8-diazabicyclo[5.4.0]undec-7-ene or salts thereof.
 8. A layeredarticle according to claim 1 wherein the dehydrofluorinating compositionis present in an amount of from 0.25 to 7 parts per hundred of thecurable elastomer.
 9. A layered article according to claim 1 wherein thedehydrofluorinating composition comprises both an organo onium and anamidine.
 10. A layered article according to claim 1 wherein thefluoropolymer is derived from an interpolymerized unit of at least onefluorine-containing olefinically unsaturated monomer provided that if aperfluorinated monomer is present then at least one monomer thatcontains hydrogen is also present with the further proviso that thefurther monomer is neither vinylidene fluoride nor a monomer that, whenpolymerized, forms a microstructure similar to polymerized vinylidenefluoride.
 11. A layered article according to claim 1 having aninterlayer adhesion between the first layer and the second layer of atleast 2 Newtons per cm of width.
 12. A layered article according toclaim 1 wherein the first layer is the dehydrofluorinated productresulting from interaction between the fluoropolymer and thedehydrofluorinating composition.
 13. A layered article comprising afirst layer comprising a fluoropolymer derived from interpolymerizedunits of a (i) first monomer selected from the group consisting ofhexafluoropropylene, a perfluoroalkyl vinyl ether, a branchedperfluorinated monomer, and combinations thereof, (ii) a second monomerselected from the group consisting of tetrafluoroethylene,chlorotrifluoroethylene, a fully halogenated olefinically unsaturatedmonomer containing two carbon atoms and combinations thereof, (iii) athird monomer selected from the group consisting of ethylene, propylene,a non-halogenated olefinically unsaturated monomer and combinationsthereof, and a second layer in contact with the first layer, the secondlayer comprising a mixture of a curable elastomer and adehydrofluorinating composition, wherein the dehydrofluorinatingcomposition is selected from the group consisting of an organo-oniumcompound, an amidine compound, or a mixture of one or more of anorgano-onium compound and an amidine compound.
 14. A layered articleaccording to claim 13 wherein the fluoropolymer comprisesinterpolymerized units derived from (i) hexafluoropropylene, (ii)comprising tetrafluoroethylene, (iii) comprising ethylene, wherein thehexafluoropropylene content of the fluoropolymer is at least 22% and theethylene content of the fluoropolymer is at least 14%.
 15. A layeredarticle according to claim 14 wherein the hexafluoropropylene content ofthe fluoropolymer is at least 24%.
 16. A layered article according toclaim 13 wherein the fluoropolymer comprises interpolymerized unitsderived from (i) hexafluoropropylene, (ii) tetrafluoroethylene, (iii)ethylene, wherein the melt point of the fluoropolymer is no more than190° C.
 17. A layered article according to claim 16 wherein thefluoropolymer melt point is no more than 170° C.
 18. A layered articleaccording to claims 1 or 13 wherein the article is a hose, a gasket, afilm, or a container.